Thermostatic regulating device.



2 SHEETS8HEBT 1.

Patented Aug. 3, 1909.

APPLIUATION FILED SEPT. 28, 1908.

' w. H. CARRIER & E. W. COMFORT.

THERMOSTATIG REGULATING DEVICE.

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W. H. CARRIER 6; E. W. COMFORT.

THBRMOSTATIO REGULATING DEVICE.

APPLICATION FILED BEPT.BB,1908.

Patented Aug. 3, 1909.

2 SHEETS-SHEET 2.

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UNITED sTAT s PATENT OFFICE.

. WILLIS H. CARRIER AND EDWARD W. COMFORT, OF BUFFALO, NEW YORK,ASSIGNORS TO B Ul l A LO FOltG E UOM IA N Y,

OF llUFliALO, NEW YORK.

THEBMOSTATIC REGULATING DEVICE.

Specification of Letters Patent.

Patented Aug. 3, 1909.

Application filed September 28, 1908. Serial No. 455,208.

To all whom it may concern:

Be it known that we, Wnmas ll. Claiunnu and EnwARn W. (JoMrou'r,citizens of the United States, residing at Buffalo, in the county ofErie and State of New York, have invented a new and useful Improvementin Thermostatic Regulating Devices, of which the following is a secification.

This invention re ates to thermostatic instruments which are influencedby the temperature and hygrometric conditions of the surroundingatmosphere and are primarily utilized for regulating the humidit of theair. An instrument of this sort-is iscloscd in Patent No. 896,690,granted Aug. 18, 1908, to W. H. Carrier, assignor to Builalo ForgeCompany, which com )IlSGS two expansible elements, one aflccte by theactual or dry bulb temperature of the surrounding air, and the ot oraffected by the lower wet bulb temperature of the air produced byevaporating moisture around this element. As the evaporation of themoisture is more or less rapid, depending upon the hygrometric conditionof the air, it follows that the wet bulb temperature of the air rises orfalls relative to the dry bulb temperaturein proportion as the air ismore or less humid. Consequently the relative exansion of contraction ofthe two elements is dependent upon the relation existing between thetemperature and the humidity of the air affecting them, and the ositionof a device operated by the conjoint iflferential action of theseelements can accordingly be used through suitable instrumentalities, forregulating the humlditiy of the air. The changes in the dr an 'wet bulbtemperatures of the air w llCll take place while the pgcentage ofhumidity remains constant, r a practically fixed relation or ratio toeach ot perature, but the ratios differ for different percentages ofhumidity. Likewise the ratio of changes in the dry and wet bulbtemperatures of the air remains practically constant for the sameabsolute humidity, but differs for different absolute humidities. Insaid patented device, expansible elements having different coefiicientsof expansion are used and means are provided for chau ing the ratio ofexpansion or contraction o the two elements to correspond to difi'erentratios existing between the changes in the wet and er within ordinaryranges of temdry bulb temperatures of the air under different conditionsof humidity, so that by different adjustments of the device it willmaintain different desired hygrometric conditions notwithstanding widelluetlultious in the temperature of the air.

The object of the present invenlion is to produce a reliable andaccurate instl'llllullt of this character which is of simple andpractical construction and can be readily ad- )usted to securedifi'erentdcsired hygromctric conditions, but in which expansiblcelements can be employed having the same or unchaugcable coefficients ofexpansion. This is accomplished by )roviding two cxpansible elements,preferab y alike, termed, for convenience, the dry and the wot elements,which are affected respectively by the dry and wet bulb temperatures ofthe air and operate in opposition on the regulating device or valvethrougha lever mechanism which can be adjusted to ive different ratiosof leverage between said elements, depending upon the desired result tobe obtained.

The changes in dimensions of the thermostat elements produced byordinary temperature 'fiuctuations are, in practice, very small, andordinarily complicated mechanism operated by the expansiblc elements isrequired for effecting the humidity regu lation.

Another objectof this invention is to produce an instrument of smallsize, and compact and durable construction, which will 0 ierate inresponse to these small changes in t e expansible elements and will beefficient and reliable for humidity regulation.

In the accom anying drawings, consisting of two sheets: igure 1 is afront elevation, partly in section, of a regulating 'ustrumcnt embodyingthe invention. Fig. 2 is a sectional elevation thereof in line 22,Fig. 1. Fig. 3 is an end elevation thereof. Fig. 4 is a sectional plan,on an enlarged scale, of the regulating valve.

Like letters of reference refer to like parts in the several figures.

A and B rcpresent'respectively the socallcd dry and Wet expansibleelements, which preferably consist of similar tubes of ebonite, orpieces of other suitable nuiterial having a high coeflicient ofexpansion, and C represents a regulating device or lover. The dry andwet bulb elements A and B, as stated, are affected respectively by theactual, or dry bulb, and wet bulb temperatures of the air, provisionbeing made or evaporating moisture around the wet element, and the twoelements operate in opposition to each other on the regulating devicethrough an adjustable lever mechanlsm.

The expansible elements can be arranged and connected in different waysso that one will be thus affected by the wet bulb temperature of theair, and to allow for changmg the ratio of leverages on the regulatingdevice. In the construction shown in the drawin s, the dry element A ispivoted at one en to a post at projecting from a base or support D andis provided at its free end with a knife edge e which bears on a leverE. The element A can be swung on its pivot 0st (I to cause its knifeedge to bear on the ever at difi' rent distances from the lever fulcrum,an it is held when adjusted, b a binding nut d screwed on the pivot postThe lever E has a knife edge engagement f witha second lever F whichcarries an adjusting screw G havin a pointed end bearing against one end0 the wet element B.

he wet element B is provided at its other end with a reduced or pointedpart bearin aglainst the regulating'device or lever T e levers C, E andF are fulcrumed to posts projecting from the base, preferably y thinflat springs c, e, and f, respectively, which are xed to the levers andposts. These fulcrum springs hold the levers in lace and preventlooseness in the joints and East motion between the parts, and thespring a for the regulating lever C tends to move said lever toward andhold it against the end of the wet element B. The regulating device orlever will remain stationa or be moved in one or the other direction,depending upon the relative changes in length of the two expansibleelements caused by changes in the temperatures affecting them, and therelative leverages which they exert on the regulating device.

The free end of the re lating lever G acts as avalve to control a bleeder or escape orifice h, Fig. 4, in a branch h of a p1pe H which suplies compressed air to the actuating diap ragm or motor of theapparatus (not shown) which regulates the humidity of the air. Arestricting valve it vided in the air pipe H which permits only a verysmall quantity of air to pass to the regulating motor. If the bleederorifice is closed by the regulating device 0- the air passing therestricting valve to the'motor will operate the motor to move the artactuated thereby in one direction, w ereas if the regulatlng device 0 ismoved to open the bleeder orifice the air will escape from 'thediaphragm through the orifice faster than it can pass the restrictingvalve to the motor, thus permitting the motor to effect an isproopposite movement of the part actuated thereby. Thus the regulatingdevice C by 0 enin and closin the bleeder orifice It acts, t roug thehumi lty regulatin to effect a chan e in the huml'ity of the air. Verylittle orce is required to operate the re ulating device C and themovement thereol necessary for eflecting the regulation is'so small thatthe instrument regulates accurately and responsively to sli htfluctuations in temperature and humidity. The described means whereb themovement of the regulating lever C e ects the regulation are thereforedesirable, but the inven: tion is not restricted to these means andother instrumentalities governed by the movement of the lever C, orother part similarly actuated, can be employed for efl'ecting theregulation.

The means shown for subjecting the wet element B to the wet-bulbtemperature of the air consist of a wick I of absorbent material whichsurrounds the wet element and is kept wet by dipping into a waterreceptacle z to which water is fed from the base D, which is hollow andforms a large water reservoir. A water supply pipe K connects with thereservoir above a partition which divides the reservoir into twochambers connectin through a hole is in the artition. A valve on a pushrod is exten ing through the top of the base controls the hole is. Aspring is normally holds the valve is oil. of its seat and holds asecond valve In on the push rod against the inner end of an air ventpassage k in the top of the reservoir. To fil the reservoir the rod 7:is ushed downwardly to seat the valve is an open the air vent k, and thecock of the supply pipe K is then turned to admit water to thereservoir. When the reservoir is filled the push rod is released, whenthe reservoir will automaticall replenish the water taken from the we 1by the wick I. Air is caused' to circulate past the wet element B underashield L partially inclosing the element and through a passage Z in thebaseD to evaporate the moisture from the wick, as irator l which islocated in said passage Z. Tl ie shield L is preferably hinged to thebase so that it can be turned back out of the way to permit the wick tobe put in place. Any other suitable means can be employed for; causingthe temperature of the wet element to correspond to the wet-bulbtemperature of the air. v

The 0 eration of the instrument is as follows: .Ilhder conditions ofsaturation the dry and wet bulb temperatures'of the air are the same andany change in the actual in t e wet bulb temperature, which r in thesame change in the length of. bothpf the expansible elements A and B. Tomam tain a saturated condition ,therefore it is temperature is followedby a like clgsfe apparatus,

by annecessary for the two elements to have an equal but op ositeefl'ect on the regulating device 0, and the dry element A must beadjusted to bear on the lever E at the point marked 100 per cent., whenthe ratio of the leverages of the two elements will be equal. Changes inthe dry bulb temperature, when the humidit is less than 100 er cent.,are accompanie b changesof di erent de es in the wet bul temperature,but, as be ore stated, the changes in the dry and wet bulb temperaturesbear a definite, practically constant ratio to each other for any givenpercentage of humidity. For example, with I,

humi ity of 50 per cent. a change of 10 in the dry bulb temperature willbe accompanied by a change of 8-} in the wet bulb temperature. Tomaintain this ,humidity, therefore, the dry element is set to bear onthe lever E at the oint marked 50 )er cent., when the ratio 0 theleverages o the dry antl wet elements will be as 10 to 8%, with theresult that a 10 per cent. change in the length of the dry element willhave an effect on the regulating device C equal but opposite to an 8?,per cent. change in the wet element. In like manner, the'proper ratiosof leverages for other desired percentages of humidity are secured byadjusting the dry element to the oints on the lever E indicatin suchhumidities. The instrument can also e adjusted to maintain a desiredabsolute humidity by setting the dry element so that the ratio of theleverages of the two elements corresponds to the ratio of changes in thedry and wet bulb tem eratures which exists with such absolute ,umidity.The lever F is marked 30 D. P., 40 D. P., &c., to indicate the points atwhich the dry element should beset to maintain these respective absolutehumidities. Likewise, other desired conditions of humidity could besecured by adjustments which would give the required lever ratiosbetween the two expansible elements.

The described adjustment of the dry ele- 1 ment on the lever E merelygives the reuired ratio of leverages to com ensate for t e temperature.fluctuations. esides this adjustment, the screw G is adjusted, asindicated by raduations on its enlarged head, to proper y settheregulatin lever G to secure the necessary difference atween the wet anddry bulb temperatures for a desired humidity condition.

We claim as our invention:

1. Thecombination of two expansible elements which are separatelyinfluenced by the dry and wet bulb temperatures of the air, a devicewhich is operated by the conjoint action of said expansible elements andmeans which are adjustable to give difl erent ratios of leverage betweensaid ex ansible elements and said device, substantial y as set forth.

' 2. The combination of two expansible eledry and wet bulb temperaturesof the air, a

device which is operated by the conjoint action of said expansibleelements, and lever mechanism between said expansible elements, whichmechanism is ad'ustuble whereb said elements have an e ual at opposite eect on said device under ifi'erent'atmospheric conditions, substantiallyas set forth.

4. The combination of two expansible elements, one of which is afl'ectedby the temperaturebf the air, means for evaporating moisture in thevicinity of the other element, a device which is operated. by theconjoint action of said expansible elements, and means which areadjustable to give different ratios of leverage between said expansibleelements and said device, substantially as set forth.

5. The combination of two ex ansible elements which have the same coecient of ex- Sansion and are separately influenced by .the

ry and wet bulb temperatures of the air, a device which is operated bythe conjoint action of said expansible elements, and means which areadjustable to give different ratios of leverage between said expansible'elements and said device, substantially as set forth.

6. The combination of two ex ansible elements which have the same wecient of expension and are separately influenced by the dry and wet bulbtemperatures of the air, a device which is operated by the conjointaction of said expansible elements, and an adjustable lever mechanismfor transmitting motion from said expansible elements to sai device,substantially as set forth.

7. The combination of expansible elements which are separatelyinfluenced by difl'erent temperatures, a regulating device which isoperated by the conjoint action ofsaid expansible elements, and 'levermechanism be tween said expansible elements, which mechanism isadjustable whereby said elements have an equal but 0 posite effect onsaid regulating device an er relatively ditferent tem rature conditions,substantially as set fortlil 8. The combination of two expansibleelements which are separately influenced by the dry and wet bulbtemperatures of the air, a device which is operated by the conjointaction of said expansible elements, and lover mechanism between saidexpansible elements, one of sai elements having an adjustable connectionwith said lever mechanism, sub;

stantially asvset forth..

9. The combination of two expansible ele ments which are separatelyinfluenced by the dry and wet bulb temperatures of the air, a devicewhich is operated by the conjoint action of said expansible elements,lever mechanism between said expansible elements, which mechanism isadjustable, and means for adjusting the osition of said regulatingdevice, substantial y as set forth.

10. The combination of two expansible elements which are separatelyinfluenced by the dry and wet bulb temperatures of the air, a. devicewhich is operated by the conjoint action of said expansible elements,levers having an operative connection with each other, an adjustableconnection between one of said ex ansible elements, and one lever and anadiustable connection between the other expansible element and anotherlever, substantially as set 'forth.

11. The combination of two expansible elements which are separatelyinfluenced by the dry and wet bulb temperatures of the air, a regulatingdevice in connection with one of said expansible elements, and levermechanism between said elements having an ad- 'ustable connection withsaid other expansile element, substantially as set forth.

Witness our hands, this 23rd day of September, 1908.

WILLIS H. CARRIER. EDWARD W. COMFORT.

Witnesses:

WM. L. Fox, E. A. Voss.

